clear all
R=1; % radius
%n=20; m=20; % polar grid spacing
%[x,y,z]=cylinder(linspace(0,r,n),m);
[x,y]=meshgrid(-2:.1:2,-2:.1:2);
z=real(sqrt(R^2-x.^2-y.^2));
[x,y,z]=ellipsoid(0,0,0,8,2,2);
figure(1)
mesh(x,y,z); hold on
mesh(x,y,-z); hold off
axis equal

